The present invention relates to a method for feeding, in a product wrapping machine, a continuous band of wrapping material, the surface of which is pre-impregnated with an aromatizing substance.
The present invention is advantageously applied in the packaging of packets of items for smokers, to which the following description refers, but without restricting the scope of the invention.
More precisely, the following description refers to the packaging of cigarette packets, although the description is equally valid for the packaging of packets of cigars or other similar items.
Cigarettes fed out of a cigarette-making machine are normally fed into a wrapping machine, in which the cigarettes are arranged in groups, each group being fed to a wrapping line on which they are wrapped first with a sheet of wrapping material, which forms a kind of wrapper, then with a blank (or sheet which forms an outer wrap), which is folded around the wrapper to create a finished packet.
The sheet of wrapping material normally has an aluminum side and a paper side, respectively defining the outer and inner surfaces of the wrapper, and is fed to the wrapping line after being cut from a continuous band at a cutting station, to which the continuous band is fed after being unwound from a reel of wrapping material.
To satisfy the tastes of consumers, cigarettes are known to be aromatized using reels of wrapping material obtained by winding a continuous band whose paper side has been impregnated with the desired aromatizing substance.
Without limiting the general nature of the present description, specific reference is made to the use of menthol aromatizing substances, since these are the most in demand on the market. In particular, such aromatizing substances, normally available in solid form, as powders, are heated until they reach the liquid state, then sprayed onto a given portion of the paper side.
The use of reels of wrapping material obtained in the above-mentioned way allows cigarettes produced by common cigarette-making machines to be aromatized in a very simple, economical way, without damaging them and without necessitating any modifications to said machines. However, such a method causes frequent stoppages on known wrapping machines, since the aromatizing substance tends to stick to and may damage some operating parts of the wrapping machines.
In particular, since the known types of menthol aromatizing substances pass from the solid state to the liquid state at a relatively low temperature (46/48.degree. C. at atmospheric pressure), within the said wrapping machines they assume a semi-solid state which makes the substances particularly sticky and so likely to cause damage.
It should be noticed that during the various wrapping operations, the operating parts, especially the folding means, of the wrapping machines mainly come into contact with the metal side which, although not directly sprayed with the aromatizing substance, is still covered in it because, when the band is wound onto the reel, the two sides of the band make contact with one another.
The use of reels of wrapping material obtained in the above-mentioned way brings further disadvantages if aesthetic requirements necessitate embossing of the band unwound from the reels. Embossing operations of the known type are normally carried out using a pair of embossing rollers, positioned on opposite sides of the band to be embossed, the surfaces of the rollers worked so as to define an embossing die, designed to create a given permanent deformation on the band. Therefore, based on the above information, it is obvious that the aromatizing substance tends to clog the embossing die, compromising its correct functioning.
This disadvantage is normally overcome by heating at least one of the two embossing rollers so that the aromatizing substance in contact with the embossing die is brought to the liquid state. However, such a solution does not solve the basic problem indicated above, since, once the band has been embossed, the aromatizing substance remaining on the band cools and returns to the semi-solid state.
The aim of the present invention is to provide a method for feeding, in a product wrapping machine, a continuous band unwound from a reel obtained in the above-mentioned way, which allows the above-mentioned disadvantages to be at least partially overcome.